Add support for separate image samplers (#74)

* Add support for separate image samplers

CHANGELOG.md

@@ -7,6 +7,10 @@ adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 
+### Added
+
+- Support for separate image samplers (`SamplerState` in HLSL, `sampler` in GLSL)
+
 ### Changed
 
 - Updated `egui` to v0.26

Cargo.toml

@@ -41,8 +41,10 @@ ash-molten = "0.17"
 anyhow = "1.0"
 bmfont = { version = "0.3", default-features = false }
 bytemuck = "1.14"
+clap = { version = "4.5", features = ["derive"] }
 glam = { version = "0.25", features = ["bytemuck"] }
 half = { version = "2.3", features = ["bytemuck"] }
+hassle-rs = "0.11"
 image = "0.24"
 inline-spirv = "0.2"
 log = "0.4"

contrib/rel-mgmt/run-all-examples

@@ -22,6 +22,9 @@ cargo run --example cpu_readback
 cargo run --example subgroup_ops
 cargo run --example bindless
 cargo run --example image_sampler
+cargo run --example image_sampler -- --hlsl
+cargo run --example image_sampler -- --separate
+cargo run --example image_sampler -- --hlsl --separate
 cargo run --example vertex_layout
 cargo run --example font_bmp
 cargo run --example egui

examples/image_sampler.rs

@@ -1,6 +1,8 @@
 mod profile_with_puffin;
 
 use {
+    clap::Parser,
+    hassle_rs::compile_hlsl,
     inline_spirv::inline_spirv,
     screen_13::prelude::*,
     std::{
@@ -16,6 +18,12 @@ use {
 /// instead use use name suffixes such as _llr or _nne for linear/linear repeat or nearest/nearest
 /// clamp-to-edge.
 ///
+/// You may run this example program with either --hlsl or --separate arguments as follows:
+///
+/// cargo run --example image_sampler -- --hlsl --separate
+///
+/// Run with --help for more information.
+///
 /// See min_max.rs for more advanced image sampler usage.
 fn main() -> anyhow::Result<()> {
     pretty_env_logger::init();
@@ -74,6 +82,114 @@ fn create_pipeline(
     device: &Arc<Device>,
     sampler_info: impl Into<SamplerInfo>,
 ) -> anyhow::Result<Arc<GraphicPipeline>> {
+    let args = Args::parse();
+
+    let mut frag_shader = match (args.hlsl, args.separate) {
+        (true, true) => {
+            // HLSL separate image sampler
+            Shader::new_fragment(
+                inline_spirv!(
+                    r#"
+                struct FullscreenVertexOutput
+                {
+                    float4 position : SV_Position;
+                    [[vk::location(0)]] float2 uv : TEXCOORD0;
+                };
+
+                [[vk::binding(0, 0)]] Texture2D screenTexture : register(t0);
+                [[vk::binding(1, 0)]] SamplerState textureSampler : register(s0);
+
+                float4 main(FullscreenVertexOutput input)
+                    : SV_Target
+                {
+                    return screenTexture.Sample(textureSampler, input.uv);
+                }
+                "#,
+                    frag,
+                    hlsl
+                )
+                .as_slice(),
+            )
+        }
+        (true, false) => {
+            // HLSL combined image sampler: inline_spirv uses shaderc which does not support this, so
+            // we are using hassle_rs which uses dxc. You must follow the instructions listed here to
+            // use hassle_rs:
+            // See: https://github.com/Traverse-Research/hassle-rs
+            // See: https://github.com/microsoft/DirectXShaderCompiler/wiki/Vulkan-combined-image-sampler-type
+            // See: https://github.com/google/shaderc/issues/1310
+            Shader::new_fragment(
+            compile_hlsl(
+                "fragment.hlsl",
+                r#"
+                struct FullscreenVertexOutput
+                {
+                    float4 position : SV_Position;
+                    [[vk::location(0)]] float2 uv : TEXCOORD0;
+                };
+
+                [[vk::combinedImageSampler]][[vk::binding(0, 0)]]  Texture2D<float4> screenTexture : register(t0);
+                [[vk::combinedImageSampler]][[vk::binding(0, 0)]]  SamplerState textureSampler : register(s0);
+
+                float4 main(FullscreenVertexOutput input)
+                    : SV_Target
+                {
+                    return screenTexture.Sample(textureSampler, input.uv);
+                }
+                "#,
+                "main", "ps_5_0", &["-spirv"], &[],
+            )?
+            .as_slice(),
+        )
+        }
+        (false, true) => {
+            // GLSL separate image sampler
+            Shader::new_fragment(
+                inline_spirv!(
+                    r#"
+                #version 460 core
+
+                layout(binding = 0) uniform texture2D image;
+                layout(binding = 1) uniform sampler image_sampler;
+                layout(location = 0) in vec2 vk_TexCoord;
+                layout(location = 0) out vec4 vk_Color;
+
+                void main() {
+                    vk_Color = texture(sampler2D(image, image_sampler), vk_TexCoord);
+                }
+                "#,
+                    frag
+                )
+                .as_slice(),
+            )
+        }
+        (false, false) => {
+            // GLSL combined image sampler
+            Shader::new_fragment(
+                inline_spirv!(
+                    r#"
+                #version 460 core
+
+                    layout(binding = 0) uniform sampler2D image;
+                    layout(location = 0) in vec2 vk_TexCoord;
+                    layout(location = 0) out vec4 vk_Color;
+
+                    void main() {
+                        vk_Color = texture(image, vk_TexCoord);
+                    }
+                "#,
+                    frag
+                )
+                .as_slice(),
+            )
+        }
+    };
+
+    // Use the builder pattern to specify an image sampler at the combined binding index (0) or
+    // separate binding index (1).
+    let sampler_binding = args.separate as u32;
+    frag_shader = frag_shader.image_sampler(sampler_binding, sampler_info);
+
     Ok(Arc::new(GraphicPipeline::create(
         device,
         GraphicPipelineInfo::default(),
@@ -100,24 +216,7 @@ fn create_pipeline(
                 )
                 .as_slice(),
             ),
-            Shader::new_fragment(
-                inline_spirv!(
-                    r#"
-                    #version 460 core
-
-                    layout(binding = 0) uniform sampler2D image;
-                    layout(location = 0) in vec2 vk_TexCoord;
-                    layout(location = 0) out vec4 vk_Color;
-
-                    void main() {
-                        vk_Color = texture(image, vk_TexCoord);
-                    }
-                    "#,
-                    frag
-                )
-                .as_slice(),
-            )
-            .image_sampler(0, sampler_info),
+            frag_shader,
         ],
     )?))
 }
@@ -153,3 +252,15 @@ fn read_image(device: &Arc<Device>, path: impl AsRef<Path>) -> anyhow::Result<Ar
 
     Ok(image)
 }
+
+#[derive(Parser, Debug)]
+#[command(version, about, long_about = None)]
+struct Args {
+    /// Use HLSL fragment shaders instead of the default (GLSL).
+    #[arg(long)]
+    hlsl: bool,
+
+    /// Use separate image sampler objects instead of the default (combined image sampler objects).
+    #[arg(long)]
+    separate: bool,
+}

src/driver/descriptor_set.rs

@@ -59,6 +59,14 @@ impl DescriptorPool {
             pool_size_count += 1;
         }
 
+        if info.sampler_count > 0 {
+            pool_sizes[pool_size_count] = vk::DescriptorPoolSize {
+                ty: vk::DescriptorType::SAMPLER,
+                descriptor_count: info.sampler_count,
+            };
+            pool_size_count += 1;
+        }
+
         if info.storage_buffer_count > 0 {
             pool_sizes[pool_size_count] = vk::DescriptorPoolSize {
                 ty: vk::DescriptorType::STORAGE_BUFFER,
@@ -214,6 +222,7 @@ pub struct DescriptorPoolInfo {
     pub input_attachment_count: u32,
     pub max_sets: u32,
     pub sampled_image_count: u32,
+    pub sampler_count: u32,
     pub storage_buffer_count: u32,
     pub storage_buffer_dynamic_count: u32,
     pub storage_image_count: u32,
@@ -229,6 +238,7 @@ impl DescriptorPoolInfo {
             + self.combined_image_sampler_count
             + self.input_attachment_count
             + self.sampled_image_count
+            + self.sampler_count
             + self.storage_buffer_count
             + self.storage_buffer_dynamic_count
             + self.storage_image_count

src/driver/graphic.rs

@@ -5,8 +5,11 @@ use {
         device::Device,
         image::SampleCount,
         merge_push_constant_ranges,
-        shader::{DescriptorBindingMap, PipelineDescriptorInfo, Shader, SpecializationInfo},
-        DriverError,
+        shader::{
+            DescriptorBindingMap, DescriptorInfo, PipelineDescriptorInfo, Shader,
+            SpecializationInfo,
+        },
+        DescriptorBinding, DriverError,
     },
     ash::vk,
     derive_builder::{Builder, UninitializedFieldError},
@@ -363,6 +366,7 @@ pub struct GraphicPipeline {
     pub name: Option<String>,
 
     pub(crate) push_constants: Vec<vk::PushConstantRange>,
+    pub(crate) separate_samplers: Box<[DescriptorBinding]>,
     pub(crate) shader_modules: Vec<vk::ShaderModule>,
     pub(super) state: GraphicPipelineState,
 }
@@ -459,6 +463,13 @@ impl GraphicPipeline {
             }
         }
 
+        let separate_samplers = descriptor_bindings
+            .iter()
+            .filter_map(|(&descriptor_binding, (descriptor_info, _))| {
+                matches!(descriptor_info, DescriptorInfo::Sampler(..)).then_some(descriptor_binding)
+            })
+            .collect();
+
         let descriptor_info = PipelineDescriptorInfo::create(&device, &descriptor_bindings)?;
         let descriptor_sets_layouts = descriptor_info
             .layouts
@@ -560,6 +571,7 @@ impl GraphicPipeline {
                 layout,
                 name: None,
                 push_constants,
+                separate_samplers,
                 shader_modules,
                 state: GraphicPipelineState {
                     layout,